WCF反序列化正在进行中。如何在不调用其构造函数的情况下实例化数据协定类型的实例?
例如,考虑以下数据合同:
[DataContract] public sealed class CreateMe { [DataMember] private readonly string _name; [DataMember] private readonly int _age; private readonly bool _wasConstructorCalled; public CreateMe() { _wasConstructorCalled = true; } // ... other members here }
通过获取此对象的实例时,DataContractSerializer您会看到字段_wasConstructorCalled为false。
DataContractSerializer
_wasConstructorCalled
false
那么,WCF如何做到这一点?这是其他人也可以使用的技术,还是对我们隐藏?
FormatterServices.GetUninitializedObject()将创建实例而不调用构造函数。我通过使用Reflector并深入研究了一些核心.Net序列化类来找到此类。
FormatterServices.GetUninitializedObject()
我使用下面的示例代码对其进行了测试,看起来效果很好:
using System; using System.Reflection; using System.Runtime.Serialization; namespace NoConstructorThingy { class Program { static void Main() { // does not call ctor var myClass = (MyClass)FormatterServices.GetUninitializedObject(typeof(MyClass)); Console.WriteLine(myClass.One); // writes "0", constructor not called Console.WriteLine(myClass.Two); // writes "0", field initializer not called } } public class MyClass { public MyClass() { Console.WriteLine("MyClass ctor called."); One = 1; } public int One { get; private set; } public readonly int Two = 2; } }
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